Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Initial Soc Percent (%)

Required number input.

Discharge Current Amperes (A)

Required number input.

Elapsed Hours (h)

Required number input.

Capacity Amp Hours (Ah)

Required number input.

Ideal battery state of charge after a constant discharge current, using nominal amp-hour capacity; ignores coulombic losses and aging. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Remaining Soc Percent (%)

The resulting remaining soc percent returned as a number.

• Battery voltage, capacity, resistance, state of charge, and energy density depend on chemistry, series-parallel topology, temperature, rate, cutoff, balance, aging, and measurement method. Cell mismatch and protection limits must be evaluated separately.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Battery Parallel Capacity

  Nominal parallel pack amp-hour capacity from identical branch capacity and integer branch count.

• Battery Internal Resistance

  Apparent battery DC internal resistance from open-circuit and loaded terminal voltages at a measured discharge current.

• Otto Cycle Efficiency

  Ideal air-standard Otto-cycle thermal efficiency 1−1/r^(γ−1) from compression ratio and constant heat-capacity ratio.